Dr Simon Webb - research
We use molecular self-assembly to create materials that mimic biological membranes and improve our understanding of important biological processes.
Current research themes include: elucidating the role of 'cooperativity' during the binding of multivalent ligands to phospholipid bilayers; understanding the role of 'lipid rafts' in cellular recognition and reactivity; creating synthetic ion channels; using magnetic nanoparticle-vesicle assemblies to create magnetically-responsive biomaterials for cell culture; using synthetic peptides as transmembrane information relays.
Descriptions of some ongoing projects are given below. For further information on the group and our research, please visit: www.webblab.org
Membrane Recognition and Reactivity: We aim to quantify the effect of lipid rafts on the multivalent recognition of external ligands and the reactivity of soluble enzymes. We have shown that patches of synthetic lipids can strengthen multivalent molecular recognition and enhance enzyme reactivity. Nonetheless, any enhancement of multivalent recognition/enzyme reactivity depends upon ligand/enzyme geometry and the strength of the interaction between the ligand and membrane-bound receptors. See: J. Am. Chem. Soc. 2012, 134, 13010-13017.
Membrane Communication: Controlled communication between cells is vital for a host of biological processes, and two key methods used by cells to communicate are the transport of ions across the membrane or conformational/positional changes in membrane proteins. To replicate the former, we are developing synthetic ion channels which can be opened and closed by external stimuli. To understand the latter, we aim to use external ligands to induce conformation change in membrane-spanning peptides, producing signals that are transmitted across bilayers and initiate a cascade of enzymatic transformations. See:Nature Chem. 2013, 5, 853-860.
Bionanotechnology and Biomaterials: The interface between nanotechnology and biological chemistry promises to be an exciting area for future research. We have developed magnetic nanoparticle-vesicle assemblies (MNPVs) for the magnetically triggered delivery of biochemicals to cells. MNPVs consist of 800 nm vesicles containing stored drugs that are crosslinked by 10 nm superparamagnetic magnetic nanoparticles. The nanoparticles fulfil two critical roles: (a) they allow magnetic separation of MNPVs and objects linked to them; (b) they allow non-destructive release of the vesicle contents by a 400 kHz alternating magnetic field (AMF). See: Angew. Chem. Intl. Ed. Engl. 2011, 50, 12290-12293.